Re: [PATCH] fix misalignment in pxamci

["pHilipp Zabel" <philipp.zabel@gmail.com>]

On Mon, Jul 28, 2008 at 6:23 PM, Uli Luckas <u.luckas@road.de> wrote:
> On Saturday, 5. July 2008, pHilipp Zabel wrote:
>> On Sat, Jul 5, 2008 at 2:19 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
>> > Hi,
>> > Philipp Zabel finally made the pxamci issue clear. It turned out, that
>> > pxamci needs the DMA destination address to be aligned to 8 bytes. In
>> > some cases it happened, that the address was aligned to 4 bytes causing
>> > controller to incorrectly transfer data (and resulting into error like
>> > "mmc0: unrecognised SCR structure version 1"). The following patch allows
>> > to debug this issue and moreover fixes it by moving one 4 byte entry of
>> > mmc_card structure, aligning the DMA destination back to 8 bytes.
>> >
>> > Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
>>
>> We can enable byte aligned transfers on the DMA controller. This is
>> what I came up with yesterday:
>> (sorry for wrapped lines - the proper patch should probably be a
>> combination of both
>> warning/DALGN handling and and moving something in mmc_card around).
>>
> Hi Philipp,
> this driver is not only for pxa27x but for pxa25x as well and pxa25x can't
> handle unaligned DMA.
> Shouldn't Marek Vasut's patch be included for the PXA25x case?

Argh, DALGN shouldn't be defined in pxa-regs.h. We really need an
aligned SCR target then. Pierre, is there any way we can have the MMC
core align DMA targets for pxa25x?

Just moving elements of the mmc_card structure around seems to be good
enough, but I fear this will break again as soon as the next person
forgets about pxamci's special needs on pxa25x.

regards
Philipp